Effects of different proteases on iron absorption property of egg white hydrolysates

Iron deficiency in pernicious anemia: Specific features of iron deficient patients and preliminary data on response to iron supplementation

BACKGROUND & AIMS

While vitamin B12 (B12) deficiency is considered as the hallmark of pernicious anemia (PA), iron deficiency (ID) is also prevalent. Indeed, this auto immune gastritis is responsible for parietal cell atrophy and increase in gastric pH, leading to impaired iron absorption. We compared PA patients' features according to their iron status at PA diagnosis, and we assessed the iron status recovery after oral or intravenous iron supplementation.

METHODS

We prospectively included patients presenting with a newly diagnosed PA in a tertiary referral hospital between November 2018 and October 2020. Iron status was assessed at PA diagnosis then regularly during a standardized follow-up. In case of ID, the decision of treatment with oral and/or intravenous iron supplementation was left to the clinician convenience.

RESULTS

We included 28 patients with newly diagnosed PA. ID was observed in 21/28 (75.0%) patients: from the PA diagnosis in 13 patients, or during the follow-up in 8 patients. Iron deficient PA patients had higher plasma B12 (p = 0.04) and lower homocysteine levels (p = 0.04). Also, ID was independently associated with the 'APCA (anti-parietal cell antibodies) alone' immunological status (absence of anti-intrinsic factor antibodies) after adjustment for age, gender and B12 level (aOR 12.1 [1.1-141.8], p = 0.04). High level of APCA was associated with lower ferritin level. After 3 months of supplementation, 3/11 PA patients normalized the iron status with oral iron supplementation, versus 7/8 with intravenous iron supplementation (p = 0.02).

CONCLUSION

The high frequency of iron deficiency in PA highlights the interest of regular assessment of iron status in this condition. ID was associated with a profile including APCA alone and less pronounced B12 deficiency. Intravenous iron supplementation seemed to be more efficient than an oral supplementation in these preliminary data.

Evaluation of egg white hydrolysates on the hepatoprotective effect in vitro and in vivo

The small molecule characteristics and nutritional value of egg white hydrolysates have been widely used. In the present study, in vitro and in vivo models were used to investigate the hepatoprotective effect of egg protein hydrolysate (EWH) by regulating the expression of antioxidant enzymes. The in vitro experiment results showed that 0.1, 0.5, and 1 mg/mL of EWH enhanced antioxidant activity in HepG2 cells by increased glutathione peroxidase (GPx) activity and reduced glutathione (GSH) levels. The in vivo experiment results showed that EWH (L) (38.5 mg/kg BW) and EWH (H) (385 mg/kg BW) alleviated carbon tetrachloride (CCl4)-induced hepatotoxicity in SD rats through reduced levels of serum aspartate aminotransferase (AST) alanine aminotransferase (ALT), and lipid peroxidation products malondialdehyde (MDA). In addition, EWH also ameliorates CCl4-induced hepatotoxicity in SD rats by increasing the antioxidant activity of GSH levels with a decrease in oxidized glutathione (GSSG) levels. Besides, EWH ameliorates liver tissue injuries by CCl4-induction. EWH has the highest glutamic acid in free amino acid composition, the second highest was aspartic acid, and the third was cystine, 204, 141, and 125 mg/100 g, respectively. These results suggest EWH has hepatoprotective potential through reduced lipid peroxidation products and enhanced antioxidant activity.

Investigation of the optimal production conditions for egg white hydrolysates and physicochemical characteristics

This study aimed to investigate the potential of egg white protein hydrolysate (EWH) as a functional food by identifying the optimum production conditions for EWH with response surface methodology (the results of the sensory evaluation were considered as an essential quality indicator). At the same time, its physicochemical and biological activity was also evaluated. The optimal economic production conditions were selected: substrate concentration of 12.5%, enzyme content of 7.5%, and hydrolysis time at 100 min. The degree of hydrolysis (DH %) was 13.51%. In addition, to the better acceptance of the evaluation, it also helps to reduce the production cost of the protein hydrolysate, which is beneficial to future processing and applications. The antioxidant capacity experiments showed that EWH has good antioxidant activity, which presents a dose-dependent relationship. Hence, this study provides a theoretical basis for future research and application of EWH for processing applications, including dietary supplementation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05708-0.

Application of egg white hydrolysate (EWH) to improve frothing functionality of pasteurized liquid egg in large quantity production

Sterilized Liquid Eggs (SLE) are convenient for the baking process by minimizing the food safety risks of fresh eggs. Although these advantages were encouraging, the thermal effects of the pasteurization process had a negative impact on the functionality of the egg whites, thus making them unattractive to the food industry. Therefore, our previous study found that adding 1-5% egg white hydrolysate (EWH) contributed to the foaminess and stability in SLE. This primary purpose of this study was to confirm the feasibility of applying the optimum concentration of EWH for simultaneous evaluation and shelf life for batch production of SLE. The physical characteristics of the foam were analyzed by adding 1 ± 0.2% of EWH to SLE, and it was found that the foam with 1% EWH had better stability (low drainage), better viscosity, and similar distribution of foam bubbles size in the microstructure. No Salmonella infection has been found during the shelf life of 7 days. In addition, the highest overall acceptability has obtained using the large quantity produced SLE with 1% EWH to produce spoon cookies, followed by sensory evaluation. The cross-sectional height of the cookie and the distribution of holes in the structure were in line with those of the non-sterilized liquid egg white (NSLE). Hence, adding 1% EWH was found to the optimum concentration, which provides good foaming performance and stability of SLE. This study conveys a positive assessment to SLE producers and potential users, as it will increase their profitability economically while meeting the market challenges.

Effectiveness of enzymes on structural, functional and creep-recovery behavior of freshly prepared meringue's batter using liquid egg albumen

In this research, the impacts of varying concentration of phospholipase A₂ (PLA), protease and lipase enzyme-treated liquid egg white (LEW) were prepared using meringue batters. The gelling physico-chemical, and rheological properties such as rheological creep-recovery compliance behavior, color value (L^*, a^*, b^*, ∆E^*, Chroma, Hue and WI), gelling strenght, pH value, gelling index as TPA parameter and specific density of freshly prepared meringue batter were analyzed. The specific density of meringue batter of control (0.49 ± 0.01) was significantly decreased (P < 0.05) after enzyme treatments of PLA (0.39 ± 0.01), lipase (0.33 ± 0.01), and protease (0.37 ± 0.01). Also, the enzymatic treatment significantly decreased the b^* values from - 0.08 ± 0.07 to - 0.76 ± 0.04, - 0.70 ± 0.06, and - 0.73 ± 0.03, respectively. The Burgers model was used to characterize rheological behavior of enzyme treated and freshly prepared meringue samples. Creep-recovery responses of samples were satisfactory (R² > 0.99) for evaluation of creep-recovery behavior. This research points out the efficacy of lipase pre-treated LEW in meringue preparation on improving functionality such as batter density and gelling properties.

Improvement of Foaming Characteristics and Stability of Sterilized Liquid Egg with Egg White Hydrolysate (EWH)

A pasteurized liquid egg leads to protein denaturation and degradation of processing properties, whereas non-pasteurized eggs may have food safety risks. If the negative impact of the pasteurization process on liquid eggs can be reduced, for example, the loss of stability and foamability, companies will be willing to purchase pasteurized eggs, thereby reducing food safety risks. Therefore, in this study, specific hydrolyzation conditions were used to produce egg white hydrolysate (EWH) with a lower molecular mass of amino acid and peptide fragments, and the effects of various concentration of EWH refilling on pasteurized liquid egg properties were investigated. The results showed that up to 30.1% of EWH was hydrolyzed by protease A and papain. Adding 1% (w/w) EWH can improve the negative charge potential value, surface tension, viscosity, and weight loss analysis of the sample. In addition, the cake structure and the appearance was acceptable to consumers. Therefore, to ensure its efficient use in the baking industry and considering the cost and stability, 1% (w/w) EWH was chosen as the best concentration.

Enzymatic treatment of pork protein for the enhancement of iron bioavailability

The typical intervention for iron-deficiency anaemia is through oral supplementation with iron salts, which have unpleasant side effects. Therefore, there is a need for the development of supplements which will be absorbed more effectively and may have fewer side effects. This study investigated the effects of partially hydrolysed pork proteins on the bioavailability of non-haem iron. The peptides were derived using either pepsin or a combination of bacterial and fungal proteases, and their ability to deliver iron was evaluated in a rat intestine epithelial tissue model. The greatest iron absorption was achieved with peptides hydrolysed by pepsin of low molecular weight (<6-8 kDa). The peptides hydrolysed with bacterial and fungal enzymes may have bound to the iron too strongly, affecting bioavailability. Finally, hydrolysing proteins using pepsin in the presence of iron produces a complex that resulted in more ferritin expression than mixing the peptides with iron after hydrolysis.